public class Circle extends Shape{
  public static final double ID = 3.14;
  public int r ;

    public Circle(int r) {
        this.r = r;
    }

    @Override
    public void draw() {
        System.out.println("圆的半径 = "+ r);
    }

    @Override
    public void calcArea() {
       area = ID * r * r;
    }
}
